Why Exercise Protects Your Brain’s Health (and What Kind Is Best)

You’ve taken to heart recommendations to get at least 150 minutes of moderate-intensity aerobic physical activity a week to improve your physical fitness. What you might not realize is that with every step you take, every mile you pedal or every lap you swim around the pool, you’re enhancing your cognitive fitness. Recent studies suggest that the activities you do to improve your body also benefit your brain.

“We know that physical exercise, and aerobic exercise in particular, is very beneficial for maintaining brain health, even in people who are at risk for developing dementia and Alzheimer’s disease (AD),” says Aaron Bonner-Jackson, PhD, a neuropsychologist with Cleveland Clinic’s Lou Ruvo Center for Brain Health. “You can make a major difference in terms of how your body is functioning and, as a result, how your brain is functioning.”

So, to preserve your cognitive health, your best bet is to work out your body and your mind through regular exercise and mentally and socially stimulating activities.

In a recent study, 454 older adults underwent yearly physical exams and cognitive tests for 20 years and agreed to donate their brains for research when they died. The participants were given accelerometers, which tracked their movement and physical activity around the clock.

Those who moved more scored better on the memory and thinking tests, and every increase in physical activity by one standard deviation was associated with a 31% lower risk of dementia, the researchers reported. The association between physical activity and cognitive function remained consistent even after the study authors accounted for the participants’ brain pathology and whether or not they had dementia, according to the study.

In another recent study, 160 sedentary older people with mild cognitive impairment were assigned to take part in aerobic exercise (three times a week for 45 minutes per session), eat a heart-healthy Dietary Approaches to Stop Hypertension (DASH) diet, combine aerobic exercise with the DASH eating pattern, or receive health education.

During the six-month study, those who followed the DASH diet alone did not improve on assessments of executive function (responsible for tasks like planning, problem-solving and multitasking), while the health-education group’s function worsened, according to the study. However, those who exercised showed improvements in thinking and memory, and those who combined exercise and the DASH diet improved even more, the researchers reported.

All of these factors can adversely affect cognition, Dr. Bonner-Jackson explains.

Exercise may provide physical benefits to the brain, too, such as increasing the thickness of the cerebral cortex and improving the integrity of your white matter, the nerve fibers that connect areas of the brain’s nerve-cell-rich gray matter. It also promotes neuroplasticity, your brain’s ability to form new neural connections and adapt throughout life. “One of the key places that happens is in the hippocampus, which is a very important area of the brain for memory,” Dr. Bonner-Jackson explains.

What’s especially encouraging is you don’t necessarily have to go overboard or meet the physical activity guidelines in order to benefit your brain.

In one recent study, researchers concluded that even among people who did not meet the activity guidelines, each hour of light-intensity physical activity and achieving 7,500 steps or more daily was associated with higher total brain volume, “equivalent to approximately 1.4 to 2.2 years less brain aging.”

“There are a lot of potential mechanisms of exercise that may be combining to benefit brain health,” Dr. Bonner-Jackson says. “In general, even in people who are at risk for development of Alzheimer’s or other dementias, it can stave off decline in some cases for many years and help people function better.”

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